A group of scientists and researchers discovered that people have been analyzing climate change models all wrong. Most are looking at "bottom-up" models that start with figuring out how much gases they think each industry is producing and then totaling that up. They suggest we need to instead use a top-down" model which calculates the amount of gases in the atmosphere and then figures out the amounts of each of the various sources. By this model, it appears that a much higher percentage comes from animal ag, particularly industrial cattle operations.